This invention is related generally to anti-glide mechanisms for institutional folding tables and, more particularly, to self-adjusting anti-glide mechanisms that is distinct from any of the supports for an institutional folding table.
Institutional tables of the type that can be folded for storage and then unfolded for use are commonly found in schools and churches across the country. These tables will often have a table top comprised of two sections hinged together. The supporting structure for many of these tables includes a central leg support and two outer leg supports. Oftentimes the outer leg supports will rest on casters which allows the table to be moved from place to place whether in a folded or erected condition.
Anti-glide devices are structures resembling a post located between the center leg support and either or both of the outer leg supports. Anti-glide devices are intended to provide many of these folding tables with additional points of contact with the floor. They are not intended to be weight supporting and are therefore distinct from leg supports or other structures that are designed to support the table or those sitting at the table when bench or individual seating is attached.
Although the casters on tables such as these are usually furnished with brake locks, such mechanisms have a tendency to wear out or are often ignored by the individuals setting up the table because of the time and inconvenience associated with setting and releasing the locks. The additional contact provided by anti-glide devices is therefore needed to prevent any unintended movement or glide of the table due to the presence of the casters on both outer supports.
On many institutional folding tables, however, manufacturing irregularities will have resulted in the anti-glide devices being constructed with lengths unequal to each other or not equal to that of the center and outer leg supports. As a result, an anti-glide device may either not contact the floor if shorter than the center or outer supports or not permit the center and outer supports themselves from firmly contacting the floor if longer than any of them.
In addition, even when the leg supports and the anti-glide devices are of equal length, similar results as those above will follow should the floor on which the table rests be uneven. A depression in the surface beneath an anti-glide device will give the appearance that the support is too short to make contact with the floor. A rise in the surface beneath an anti-glide device, on the other hand, will suggest that the support is too long and will similarly cause the center and outer supports to be unable to make firm contact with the floor beneath them.
With many institutional folding tables, bench or individual seating is an integral part of the structure. Consequently, another shortcoming in the operation of anti-glide devices occurs when any weight is added to the bench or seats under which an anti-glide device of greater length than each of the supports. In this situation, not only does the anti-glide device prevent full contact by the supports with the supporting surface, but the forces on the device will often leave holes or indentations in the floor covering beneath it or oftentimes result in permanent structural damage to the device itself. This type of damage is aggravated further by any elevation in the surface by a rise or bump in the floor at that point.
This invention addresses such problems and shortcomings in a simple and inexpensive manner.
It is a primary object of this invention to provide a self-adjusting anti-glide apparatus for use on an institutional folding table that overcomes some of the problems and shortcomings of the prior art, including those mentioned above.
Another object of this invention is to provide an anti-glide apparatus for use on an institutional folding table that automatically adjusts for unevenness in the support surface on which the table rests.
Another object of the invention is to provide a novel anti-glide apparatus for use on an institutional folding table that is self-adjusting for differences between the length of the apparatus with that of similar devices attached to the table or with that of any of the supports for the table.
Another object of the invention is to provide an exceptional anti-glide apparatus for use on an institutional folding table that reduces stress placed on the anti-glide device and on the floor beneath the device during normal operation so as to minimize damage to those structures.
Another object of this invention is to provide a self-adjusting anti-glide apparatus for use on an institutional folding table that permits contact be made with the support surface at all times, irrespective of a certain degree of unevenness in this surface, so as to inhibit any movement by the table across the surface when there are leg supports mounted on casters.
Another object of the invention is to provide an improved anti-glide apparatus that is self-adjusting and yet is simple to manufacture, easy to install and maintain, as well as highly reliable to operate.
This invention is for an anti-glide apparatus to be used on an institutional folding table of the type having a top in sections and having top supports, the top supports being the only members of the table that support the top sections by extending between the top sections and the supporting surface such as a floor. Moreover, the table is of the type where the top sections are hinged together so that the table can be opened and closed.
The anti-glide apparatus is comprised of an upper member that is attached to the table, where the upper member has a central axis and is distinct from any of the top supports, and of a lower member that is connected to the upper member in a fashion where it is free at all times to slidably extend and retract within limits in a direction parallel with the axis of the upper member. This freedom of movement allows the lower member to make frictional contact with the supporting surface for the table.
In one preferred embodiment, the upper member and lower member of the anti-glide apparatus are tubular, with the upper member slidably disposed within the lower member in a telescoping relationship. In such an embodiment, the lower member is secured to the upper member by a fastener that is inserted through a fastener-aperture on the lower member and a fastener-slot on the upper member. As a result of this mode of attachment, the limits of extension and retraction for the lower member will be the length of the fastener-slot.
In certain preferred forms of this embodiment, the anti-glide apparatus is further comprised of a spring member mounted within the lower member. This feature is adapted to bias the lower member in a downward direction. One highly preferred form of this embodiment uses a coil spring for the spring member, the coil spring being engaged to a base of the upper member at one of its ends and to a base of the lower member at its opposite end. It is also highly preferred that the spring member consist of a plurality of spring washers or be made from polyurethane.
In an alternative embodiment that is most preferred, the anti-glide apparatus is further comprised of a spring member that is mounted around the outside of the upper member. The spring member is mounted to the upper member in a fashion that biases the lower member in a downward direction.
In certain preferred embodiments of this invention, the upper member and lower member remain tubular but the lower member is slidably disposed within the upper member in a telescoping relationship. In such an embodiment, the upper member is secured to the lower member by a fastener that is inserted through a fastener-aperture on the upper member and a fastener-slot on the lower member. The limits of extension and retraction for the lower member in this form of the apparatus will be the length of the fastener-slot. It is highly preferred in this embodiment for the apparatus to also include a spring member that is mounted within the upper member to bias the lower member in a downward direction.
In another highly preferred embodiment, the upper member is disposed adjacent to the lower member. In such an embodiment, the upper member is secured to the lower member by a fastener that is inserted through a fastener-slot on the lower member and a fastener-aperture on the upper member. The limits of extension and retraction for the lower member in this form of the apparatus will also be the length of the fastener-slot. It is most preferred in this embodiment of the invention that apparatus further comprise a spring member that is mounted around the outside of the upper member. This spring member is adapted to bias the lower member in a downward direction.
One most preferred embodiment of the present invention finds that the top supports of the table include a center leg support and that this support is pivotally linked to the upper member. This mechanism insures that the anti-glide apparatus is pointing substantially downward toward the floor when the table is opened and is substantially parallel to the top sections when the table is closed. Another highly preferred embodiment finds the present invention adapted for use on an institutional folding table having top supports that include at least two outer leg supports resting on casters.
In another aspect of this invention, it is an improvement to an institutional folding table of the type having a pair of top sections, top supports for supporting the top sections, and at least one non-supporting anti-glide apparatus, wherein the anti-glide apparatus is self-adjusting. In one highly preferred embodiment, the apparatus is comprised of an upper member and a lower member where the lower member is slidably disposed with respect to the upper member so that it is free at all times to infinitely extend and retract within limits. This freedom of movement allows the lower member to make frictional contact with a supporting surface for the table.
A most preferred embodiment has the upper member slidably disposed within the lower member. In such an embodiment, the lower member is secured to the upper member by a fastener that is inserted through a fastener-aperture on the lower member and a fastener-slot on the upper member. As a result, the limit of extension and retraction for the lower member is the length of the fastener-slot. Moreover, this embodiment of the apparatus includes a spring member mounted within the lower member to bias the lower member in a downward direction.